Safety Binding for a Snowboard

ABSTRACT

The invention relates to a safety binding ( 1 ) for a snowboard, particularly a safety binding to be attached in pairs to a snowboard. The invention solves the problem of reducing force peaks on the lower extremities of the athlete, which, for example, in the event of a fall exceed a force value which can be set, and in this event also enabling a three-dimensional rotation of the lower extremities. This is achieved in that a lower binding part ( 2 ), which can be fixed to the snowboard, and an upper binding part ( 3 ), which can be fixed to the shoe, are disposed on mutually facing support surfaces in a sliding manner, wherein the support surfaces are designed as the surface elements of two spherical caps, the common center of curvature of which is located above the lower binding part. The safety binding comprises at least one elastic connecting element ( 5 ), which is engaged in both binding parts and dimensioned such that it generates a physiologically allowed restoring force during the deformation thereof as a result of a displacement of the upper binding part out the normal position.

The invention relates to a safety binding for a mobile piece of sportingequipment, in particular a safety binding which can be pairwise mountedon a snowboard.

A safety binding for releasable attachment of a shoe on a piece ofsporting equipment, such as a snowboard, has the function to transmit,on one hand, steering forces from the athlete to the snowboard and, onthe other hand, to release when critical force values are exceeded inorder to prevent injury in particular to the lower extremities. Analmost lossless transmission of the steering forces from the athlete tothe piece of sporting equipment must be ensured with a safety bindingunder normal movements (not relevant for injuries).

Compared to Alpine skiing, injuries of the ankle occur more frequentlyduring snowboarding with soft boots. In particular, the injury ofligaments and bone structures in the ankle is caused by anatomicallyunfavorable rotations about all axes of the ankle and introduced forcepeaks. This injury pattern is generally known as snowboarder's ankle andoccurs primarily after a fall. It has been observed that with moreflexible snowboarding shoes the risk of injury in the event of a fall isgreater with more flexible snowboarding shoes than with inflexiblesnowboarding shoe models. However, a flexible snowboarding shoe ispreferred by the athletes in many areas of the snowboarding sport forperforming specific techniques and tricks. Reducing the injury risk ofthe ankle by using stiffer snowboarding shoes is therefore notpractical.

Several safety bindings are already known which are reported to besuitable, in particular, for snowboards. DE 39 25 164 A1 shows a bindingwith a lower binding part mounted on the piece of sporting equipment, onwhich an upper binding part is movably arranged, wherein the upperbinding part operates as receiving plate for soles and includes shoeattachment means. The upper binding part is supported by a plurality ofspring coils or in another, not further specified, manner on the lowerbinding part by way of a ball joint, whereby the shoe of the athlete canbe tilted, commensurate with the corresponding load, in any directionabout a predefinable angular range, but can also be deflected about anaxis perpendicular to the snowboard surface. This binding hasadditionally a control body which actuates a release mechanism for theshoe attachment means depending on the position of the upper bindingpart, i.e., when a presettable force value is exceeded. The binding thenreleases, when actuated, simultaneously both shoes. Disadvantageously,in the event of an unintended actuation of the binding (hard snowconditions, landings after jumps, etc.), the force transmission betweenthe athlete and the board is interrupted so that steering of the pieceof sporting equipment can no longer be guaranteed. This can represent arisk for injuries. In addition, the binding already allows smallrotation and tilt movements before actuating the binding. This wouldagain interfere with or reduce the force transmission from the athleteto the board. In addition, the construction of the binding is relativelycomplex, making it expensive to manufacture and difficult to keepoperational.

DE 39 18 939 A1 discloses a snowboard binding with a lower binding partmounted on a snowboard and an upper binding part fixedly connectablewith the shoe. Both binding parts are movably connected with one anotherby way of several elastic tension means. The pretension of the elastictension means is designed so that the upper binding part can tilt aboutthe longitudinal and transverse axes of the shoe, whereinpredeterminable force values are exceeded, and rotate up to about 10degrees about the vertical axis. This solution reduces force peaks andprevents a complete separation of the binding parts from each other. Thebinding is also not actuated even for critical force values.Disadvantageously, no means are provided for adapting the pretension ofthe elastic tension means to the individual requirements of the athlete.The binding can therefore worsen the transmission of steering forcesnecessary for snowboarding even during normal snowboarding, and cantherefore appear soft and spongy.

DE 29 510 981 U1 also discloses a relatively simple snowboarding bindingwhich is rotatable and tiltable in all three three-dimensional axes aswell as lockable in each tilt position. However, rotation and tiltmovements are prevented during the run. In this solution, an elasticrubber ring can be inserted between the binding parts to increase thefriction connection between the binding parts and lock them reliably inthe preferred position. The impact-damping effect attributed to thismeasure is, however, quite rudimentary and is unable to protect theathlete from critical force values due to the minimum tilt angleachievable in the locked state of the binding.

DE 44 06 074 C1 discloses a safety binding for a mobile piece ofsporting equipment, in particularly a snowboard, wherein an upperbinding part affixable to a shoe can also not be released from the otherbinding part attached on the piece of sporting equipment afteractuation, but is able to freely rotate about the vertical axis.However, excessive dorsal extensions and supinations are particularlyknown as injury mechanisms associated with the application of criticalaxial forces. However, the technical solution described in DE 44 06 074C1 does not offer protection precisely from such risky rotationmovements.

Based on this state of the art, it is an object of the invention toprovide a binding for securing a shoe on a mobile piece of sportingequipment, in particular a snowboard, which particularly reduces forcepeaks at the lower extremities of the athlete. However, this reductionshould only be realized when an adjustable force value (which may occur,for example, in a fall) is realized, while allowing a three-dimensionalrotation of the lower extremities. The binding to be provided shouldtherefore realize an optimal force transmission from the athlete to theboard during normal coasting and reduce the risk of injury to the lowerextremities in a crash, without releasing the foot from the piece ofsporting equipment. By keeping both feet of the athlete on the piece ofsporting equipment in the event of a possible actuation of only onebinding, force values on the respective other foot should not beincreased, which would be provoked by unfavorable lever relationships ifonly one foot were completely released from the piece of sportingequipment.

The object is attained with the invention by a safety binding having thefeatures of claim 1.

The safety binding according to the invention enables athree-dimensional rotation of the lower extremities, but allows theirmovement only when a certain force value is exceeded. This is achievedby arranging a lower binding part affixable on the piece of sportingequipment and an upper binding part affixable to a shoe are slidinglyarranged on opposing support surfaces. These support surfaces are formedas surface elements of two universal ball joints having a commoncurvature center located above the upper binding part. The safetybinding according to the invention has at least one elastic connectingelement in engagement with the two binding parts and dimensioned so asto generate a physiologically permissible restoring force during itsdeformation due to a displacement of the upper binding part from thenormal position. The safety binding according to the invention also hasat least one snap-in locking device which locks the position of theupper binding part relative to the lower binding part in apredeterminable normal position, as long as the actuating forcesoperating on the snap-in locking device are below a predeterminablethreshold value. When the snap-in locking device is actuated, the limitstops arranged on the binding parts limit the movement range of the twobinding parts relative to each other to a range compatible with theanatomical conditions.

The invention can be realized in different advantageous embodiments.Advantageously, for improving the driving characteristic and reducingforce peaks, the safety binding is adapted to the anatomy of the athleteand the common curvature center of the contact surfaces of the bindingparts is approximately at the height of the knee joint of the athletesstanding on the piece of sporting equipment.

Another embodiment allows adaptation to individual situations of theathlete, wherein the snap-in locking device has at least one movablelocking element arranged on a binding part, which is in engagement witha corresponding counter catch arranged on the lower binding part by wayof an adjustable spring force. To allow the athlete to explore thedriving conditions when the snap-in locking device is actuated, thesnap-in locking device may be manually actuatable.

In another embodiment of the invention, the movement range of the twobinding parts relative to each other is limited to a range that iscompatible with the anatomical conditions while preventing the twobinding parts from lifting off—e.g., during jumps—when the snap-inlocking device is released, by arranging limit stops in the forwardregion of the lower binding part and the rearward region of the upperbinding part, with the limit stops encompassing the respective otherbinding part in form of a hook.

The invention will now be described in more detail based on an exemplaryembodiment with reference to the appended drawings.

It is shown in:

FIG. 1 a side view of the safety binding without straps and highback,

FIG. 2 a perspective view of the safety binding without upper cover,highback and straps,

FIG. 3 a perspective view of the lower binding part,

FIG. 4 a perspective view of the elastic connecting element, and

FIG. 5 a perspective view of the limit stops limiting the movement rangeof the two binding parts relative to each other.

The safety binding 1 illustrated in FIG. 1 enables a three-dimensionalrotation of the lower extremities when a certain force value isexceeded. The lower binding part 2 is fixedly mounted on the snowboardwith screws by way of a turntable. The lower binding part 2 has (seeFIG. 3) a support surface formed as a universal ball joint with theradius R, on which the opposing support surface of the upper bindingpart 3, which is also formed as a universal ball joint with the radiusR, is supported.

The common curvature center of the contact surfaces is located above theupper binding part 3, advantageously approximately at the height of theknee joint of the athlete standing on the piece of sporting equipment.The snowboard shoe is hereby secured on the upper binding part 3 in aconventional manner with conventional straps (not illustrated).

A snap-in locking device which locks the position of the upper bindingpart 3 relative to the lower binding part 2 in a predeterminable normalposition is arranged in the safety binding. The snap-in locking devicehas at least one conical locking element arranged on the upper bindingpart 3, wherein the locking element is in engagement, due to the springforce of a spring element, with a corresponding counter catch arrangedon the lower binding part 2 and formed as a recess 4 a (see FIG. 3).When the conical snap-an element is pressed against the recess 4 a inthe lower binding part 2 by the spring force, the upper binding part 3is held in an initial position, preventing a relative movement of theupper and lower binding part relative to each other when the bindingstate is not actuated. This ensures that the force transmission betweensnowboard and snowboard is not reduced under normal driving conditions.The lower and the upper binding part 2; 3 as well as the conical snap-inlocking element are preferably constructed from POM (polyoximethylene),which is standard in the winter sports industry.

When a critical force value is exceeded, the spring force of the springelement is overcome and the conical snap-in locking element is displacedaccordingly. The rotation of the upper binding part 3 and thesnowboarding shoe attached thereto are then released. The snap-inlocking device has a device with which the critical force value foractuating the safety binding can be individually adjusted to the weightof the snowboarder and his/her level of expertise. This can be realized,for example, by adjusting the pretension of the spring element. Whenactuated, the relative movement between the upper and the lower bindingpart is damped for reducing force peaks. This is realized with anelastic connecting element 5 (FIG. 4) which is in engagement with bothbinding parts and arranged in the region of the vertical axis, aboutwhich the two binding parts can rotate after the snap-in locking deviceis actuated. In the event of an actuation, the elastic connectingelement 5 guarantees that the other binding part 3 is not completelydetached from the lower binding part 2. The elastic connecting element 5is preferably constructed as a cylindrical elastic body 5 a, withmounting elements 5 b arranged on its end faces, which allow the elasticconnecting element 5 to be safely secured to the lower and upper bindingparts 2, 3. As an alternative to a cylindrical shape of the elasticconnecting element 5, other shapes and/or a combination of severalelastic connecting elements 5 may be installed.

Increased dorsal flexion of the ankle is prevented by mechanicallylimiting the movement of the upper binding part 3 relative to the lowerbinding part 2. This limitation is attained by hook-shaped limit stops 6(FIG. 5), which are arranged in the forward region of the lower bindingpart 2 and in the rearward region of the upper binding part 3 and whicheach encompass the respective other binding part. This approach preventsthe upper binding part from becoming detached from the lower bindingpart in the event of an active vertical movement of the athlete (jump)and hence an unintentional release of the safety binding.

1. A safety binding for a mounting pairwise on a snowboard, comprising:a) a lower binding part (2) affixable on the snowboard and an upperbinding part (3) affixable to a shoe, wherein the lower and upperbinding parts have contact surfaces sliding against each other, with theopposite contact surfaces of the respective other binding part beingsupported on the contact surfaces, the contact surfaces of the two lowerand upper binding part (2; 3) are formed as surface elements of twouniversal ball joints having a common curvature center located above theupper binding part (3), b) at least one snap-in locking device whichlocks the position of the upper binding part (3) relative to the lowerbinding part (2) in a predeterminable normal position, as long as theactuating forces acting on the snap-in locking device are less than apredeterminable threshold value, c) at least one elastic connectingelement (5) in engagement with the two binding parts (2; 3) anddimensioned so as to generate a physiologically permissible restoringforce during its deformation caused by a displacement of the upperbinding part (3) from the normal position, d) limit stops (6) arrangedon the binding parts (2; 3), with the limit stops (6) limiting, when thesnap-in locking device is actuated, the movement range of the twobinding parts relative to each other to a range compatible with theanatomical conditions.
 2. The safety binding according to claim 1,wherein the common curvature center of the contact surfaces of thebinding parts is located approximately at the height of the knee jointof the athlete standing on the piece of sporting equipment.
 3. Thesafety binding according to claim 1, wherein the snap-in locking devicehas at least one movable locking element arranged on a binding part (2;3), and wherein the movable locking element is in engagement with acorresponding counter catch (4 a) arranged on the other binding part byway of an adjustable spring force.
 4. The safety binding according toclaim 1, wherein the snap-in locking device is manually actuated.
 5. Thesafety binding according to claim 1, wherein—in a top view—limit stops(6), which encompass with a hook shape the respective other bindingpart, are arranged in the forward region of the lower binding part (2)and in rearward region of the upper binding part (3).